Formation fluid sampler



g 29, 1967 F. H. REDWINE 3,338,307

FORMAT ION FLUID SAMPLER Filed Feb. 2, 1965 3 Sheets-Sheet l INVENTOR FLETCHER H. REDWINE [/97 A ORNEY Aug. 29, 1967 F. H. REDWINE 3,338,307

FORMATION FLUID SAMPLER Filed Feb. 2, 1965 5 Sheets-Sheet 2 54" 3&1 90G 31 4 INVENTOR FLETCHER H. REDWINE BY I I Hm A A MM ,z ATTORNEY Aug. 29, 1967 F. H. REDWINE FORMATION FLUID SAMPLER 5 Sheets-Sheet 3 Filed Feb. 2, 1965 RNEY INVENTOR FLETCHER H. REDWINE United States Patent 3,338,307 FORMATION FLUID SAMPLER Fletcher H. Redwine, 2002 Canterbury, Irving, Tex. 75060 Filed Feb. 2, 1965, Ser. No. 429,799 7 Claims. (Cl. 166-100) ABSTRACT OF THE DISCLOSURE A fluid sampling tool for use in a drill stem without interfering with the normal drilling and operated by means of the power of the drilling fluid. The sampling tool includes three fluid cylinders disposed transversely in a sub with each cylinder containing a piston slidably positioned therein. A sampling tube is connected to the piston of the center cylinder and a valving mechanism provides sampling fluid to a low pressure container in the sub through the sampling tube.

After a well bore has been drilled through various earth formations, it is desirable, and indeed often necessary, to take fluid samples from the formation so as to determine whether or not commercial deposits of petroleum are present in the formation. This task has heretofore been accomplished by various tools lowered into the well bore by a wire line which requires the drill stem to be removed from the hole. Other tools utilized for this purpose employ either the drill stem or a tubing string to lower the sampling tool into the well bore. Again these tools require the drill stem to first be removed, then reinserted in the borehole to lower the tool.

Previous fluid sampling tools usually use some type of device to isolate a particular zone of the well bore, such as inflatable packers, then take the sample from the isolated zone. However, some fluid sampling tools employ a sealing pad which is pressed against the wall of the well bore by some mechanism to seal off the well fluids from the formation fluids. The fluid sample is then taken from the formation through an aperture in the sealing pad.

This invention provides a fluid sampler which may be incorporated in the drill stem without interfering with normal drilling operations so that a fluid sample may be taken each time that the drill stem is either lowered into or removed from the well bore without making a special trip.

An object of the invention is to provide a fluid sample which utilizes the power of the drilling fluid to take a sample from within the formation.

A further object of the invention is to provide such a tool wherein the fluid sample is taken from the interior of the formation rather than from the face of the borehole.

Yet another object of the invention is to provide a sampling tool which seals fluids in the well bore from the sampling tube while the sample is being taken.

Another object of the invention is to provide such a tool which also functions as a drill stern stabilizer during normal operations.

Still another object of the invention is to provide an automatic valving system for taking the fluid sample after penetration of the formation.

Still another object of the invention is to provide an improved system for impounding the fluid sample as it is brought to the surface and transported to a lab.

In general, the tool constructed in accordance with the invention is comprised of a sub for connection in a drill stem through which drilling fluid may be pumped for normal drilling operations. A fluid sampling tube is connected to a piston disposed in a fluid cylinder formed in the sub. A valving means is provided to apply pressure from the drilling fluid to the cylinder to drive the sampling tube into the wall of the borehole. A receptacle at a relatively low pressure is placed in fluid communication with the end of the sampling tube by a valving mechanism so that fluids in the formation will enter the receptacle due to the higher pressure of the formation fluids.

The invention also concerns a sealing pad assembly which is driven against the wall of the borehole, around the sampling tube, the sampling tube being extended further than the sealing pad into the formation.

In accordance with another aspect of the invention, the valving means for placing the end of the sampling tube in fluid communication with the lOW pressure receptacle is comprised of a valving sleeve connected to the sealing pad and disposed around the sampling tube, and port and land means in either the valve sleeve or the sampling tube for sealing the receptacle when the sampling tube is retracted relative to the sealing pad and for establishing the fluid communication when extended.

In accordance with a more specific aspect of the invention, three fluid cylinders are disposed transversely of a housing for disposition in a borehole. Means is provided to selectively apply power fluid to the first ends of each of the cylinders. Fluid pistons are disposed in each cylinder. Piston rods extend through the second ends of th two outer cylinders and are connected to a sealing pad conforming generally to the wall of the borehole. A valve sleeve is connected to the sealing pad and is reciprocally disposed in the second end of the center cylinder. A sampling tube is connected to the piston in the center cylinder and extends through the valving sleeve. A valve is formed by port and land means on the sleeve and the sampling tube for placing the end of the sampling tube in fluid communication with a receptacle containing a low pressure when the sampling tube is extended through the sleeve. Thus when power fluid is applied to the first ends of the cylinders, the sealing pad is moved into contact with the wall of the borehole, then the sampling tube is extended through the sealing pad into the formation, and the end of the sealing tube simultaneously placed in fluid communication with the receptacle.

Additional aspects, objects and advantages of the invention will become more apparent to those skilled in the art from the following detailed description and drawings, wherein:

FIGURE 1 is a side view of a sampling tool construct ed in accordance with the present invention;

FIGURE 2 is a longitudinal sectional view of the tool of FIGURE 1;

FIGURE 3 is a sectional view taken substantially on lines 3-3 of FIGURE 2;

FIGURE 4 is a sectional view taken substantially on lines 44 of FIGURE 2;

FIGURE 5 is a sectional view taken substantially on lines 55 of FIGURE 2;

FIGURE 6 is a longitudinal sectional view of a valve element used in the tool of FIGURE 1; and

FIGURE 7 is a partial sectional view similar to FIG- URE 1 illustrating the operation of the tool of FIG- URE 1.

Referring now to the drawings, and in particular to FIGURE 1, a sampling tool constructed in accordance with the present invention is indicated generally by the reference numeral 10. The sampling tool 10 comprises a sub 12 for connection in a conventional drill stem having a box end 14 at the lower end, into which the bit will customarily be threaded, and a pin 16 at the upper end, which will customarily be threaded into the lower end of the lowermost drill collar. The sub 12 has a substantially integral body 18, as illustrated in FIGURE 2, which may be formed by any conventional techniques such as by machining and welding. A primary fluid passageway extends longitudinally through the sub 12 to pass drilling fluid from the drill stem through the bit in the conventional manner. The primary fluid passageway may be formed by a bore extending through the pin 16 at the upper end, and a bore 22 at the lower end. The bores 20 and 22 are placed in fluid communication by means of a plurality of bores 24 which extend longitudinally through the body 18 at axially offset positions as best seen in the transverse sectional views of FIGURES 3 and 4. The sub 12 has a plurality of stabilizer fins 26, preferably three as illustrated, which extend longitudinally along the body 18. The diameter of the body 18 corresponds approximately to the diameter of the drill collars, while the diameter of the fins 26 corresponds essentially to the diameter of the hole cut by the bit.

Three fluid cylinders 28, 29 and 30 are formed in the body 18 by bores 31, 32 and 33, respectively, which are parallel and disposed in a common plane intersecting the longitudinal axis of the tool 18 and bisecting the angle between two of the fins 26. The bottom of the bores 31-33 forms the first ends 34, 35 and 36 of the respective cylinders. The second ends of the cylinders 28 and 30 are formed by plugs 38 and 40 which are inserted in counterbores 42 and 44, respectively. The plugs 38 and 40 may be retained in place by snap rings 46 and 48, respectively. O-rings 50 and 52 provide a peripheral seal between the body 18 and the plugs 38 and 40. Pistons 54 and 56 are reciprocally disposed in the cylinders 28 and 30, and O-rings and 57 provide peripheral seals between the pistons and cylinders. Piston rods 58 and 60 which are connected to the pistons extend through the end plugs 38 and 40, respectively. O-rings 62 and 64 provide peripheral seals between the rods 58 and 60 and the plugs 38 and 40. Coil springs 66 and 68 are disposed in the cylinders and bias the pistons 54 and 56 toward the first ends of the cylinders.

A piston 70 is reciprocally disposed within the cylinder 29 and O-rings 72 provide a peripheral seal. An elongated sampling tube 74 is connected to the piston 70 and extends through a valve sleeve 76 which is also reciprocally disposed in the second end of the cylinder 29. O-rings 78 provide a peripheral seal between the valve sleeve 76 and the body 18. A compression coil spring 80 is disposed around the sampling tube between the piston 70 and the sleeve 76 tending to bias the two members apart. The metal liner 82 of a sealing pad indicated generally by the reference numeral 84 is connected to the valve sleeve 76. The liner 82 has an arcuate transverse cross section as best seen in FIGURE 4 to conform generally to the wall of the borehole and is connected to the ends of piston rods 58 and 60 by screws 86 and 88. Thus, the pistons 54 and 56 and the valve sleeve are interconnected by the liner 82. A resilient pad 90 is bonded or otherwise fastened to the metal liner 82 for engaging the wall of the borehole to seal the fluids in the borehole from the sampled Zone as will presently be described. The resilient pad 90 may be fabricated from a tough synthetic rubber molded onto the metal liner 82.

The tip 92 of the sampling tube 74 is preferably pointed to facilitate penetration of the wall of the borehole. A fluid passageway is formed by four bores 94 which extend from the end of the tube diagonally through the tube and exit at the interior surface of the tube. A second fluid passaegway is formed in the sampling tube 74 by a central bore 96 which communicates with the exterior surface of the tube through a plurality of radial bores 98. A centrally located tube 100 which is slidably received within a counterbore 102 to the bore 96 provides fluid communication between the bore 96 and a fluid passageway 106. O-rings 104 seal the annulus between the tube 100 and piston 70. The passageway 106 communicates with a fluid receptacle 108 which is disposed in the bore 22 in the lower end of the sub. The receptacle 108 is connected to the body 18 of the tool by a threaded coupling which may be sealed by O-rings 122 to facilitate removal of the receptacle and its contents from the tool. A check valve 110 comprised of a conventional spring-biased ball, for example, is disposed in the inlet to the fluid receptacle 108 to prevent the escape of fluids from the receptacle.

An O-ring 112 provides an annular seal between the sleeve 76 and the sampling tube 74 to seal out the well fluids outside the tool. An O-ring 114 provides an annular seal to retain the drilling fluids inside the cylinder 29. An O-ring 116 forms an annular sealing land which, in combination with the ports 94 and 98, provides a valving mechanism for closing the fluid passageway 106 when the sampling tube 74 is withdrawn as illustrated in FIG- URE 2, and for then placing the fluid passageway 106 in fluid communication with the ports 98 when the sampling tube is extended as illustrated in FIGURE 7. It will be noted that when the sampling tube is in the retracted position, the ports 94 and 98 exit at the surface of the sampling tube on opposite sides of the O-ring 116 so that fluid communication between the two ports is blocked. However, when the sampling tube extends to the right relative to the sleeve 76, illustrated in FIGURE 7 and as will hereafter be described in greater detail, the ports 94 and 98 are then positioned between the O-rings 112 and 116 and in fluid communication so that fluids can pass through the passageway comprised of ports 94, 98 and 106 to the receptacle 108.

A counterbore 124 to the bore 20 forms an annular seat 126 around the primary fluid passageway through the tool. A valve, indicate-d generally -by the reference numeral 128, which is adapted to be lowered through the drill stem by gravity or pumping mates with the seat 126 to divert high pressure drilling fluid through a port 130 and ports 131, 132 and 133 to the first ends of the cylinders 2830, respectively. Fluid communication between the primary fluid passageway at a point below the annular seat 126 and the second ends of the cylinders 2833 is provided by ports 134, 135, 136 and 137.

The valve member 128 is preferably comprised of a tubular body 144 having a major diameter portion 146 greater than that of the seat 126 and having a tapered portion 148 adapted to mate with and form a fluid seal with the seat 126. The body 144 also has a restricted neck portion 152 which forms a downwardly facing annular seat 154 internally of the tubular body. A secondary valve member 156 has a longitudinally extending fluid passageway 157 and an annular flange 158 sized and formed to mate with the downturned seat 154 when in the upper position illustrated in solid line in FIGURE 4. The body of the secondary valve member 156 is of substantially constant diameter and is slidably received in an inturned annular flange portion 160 of the valve body 14. A plurality of apertures v162 (indicated in dotted outline) extend through the annular flange 160 and have a total cross section substantially greater than the cross section of the passageway 157 through the tubular secondary valve member 156. The secondary valve member 156 is held in the upper position by a shear pin 166 which may conveniently extend through the flange portion 160 and the secondary valve member 156. The shear pin 166 is selected to shear when a pressure drop is established across the secondary valve member 156 greater than that required to operate the tool through a sampling stroke as will presently be described in detail. The upper end of the neck portion 152 may conveniently be flared at 168 to receive the point of a conventional deviation survey instrument. A number of spring wires 170 may protrude from the neck portion 152 in the conventional manner to slow the descent of the valve through the mud standing in the drill stem and also insure that the valve properly mates with the seat 126.

Extensions and 182 extend from the metal liner 82 between pairs of ears 184 and 186 which are connected to the body 18. Shear pins 188 and 190 extend through the ears and hold the extensions 180 and 182, and therefore the entire sealing pad assembly 84, in the retracted position until the pressure applied to the cylinders is sufficiently high to shear the pins as hereafter will be described in greater detail. The shear pins are preferably bradded on the ends to prevent loosening.

Operation In order to assemble the tool for operation, the receptacle 108 is filled with air at atmospheric pressure and threaded into the coupling 120. The pistons 54 and 56 and the springs 66 and 68 are inserted in the cylinders 28 and 30. The plugs 38 and 40 are then inserted in the respective counterbores and the snap rings 46 and 48 installed to secure them in place. The resilient material 90 is previously bonded to the metal liner 82. The piston 70 and sampling tube 74, together with the spring 80 are inserted in the cylinder 29. Then the sealing pad 84 is placed in position by inserting the valve sleeve 76 around the sampling tube and in the cylinder 29, and then connecting the liner 82 to the piston rods 58 and 60 by means of the screws 86 and 88 and the shear pins 188 and 190 inserted.

The tool 10 is then connected in the drill stem and lowered into the well bore. Normally the bit will be threaded into the box 14 at the lower end, and the pin 16 at the upper end will be threaded into the lowermost drill collar. The valve member 128 isretained at the surface so that normal drilling operations can be carried out by circulating drilling fluid through the primary fluid passageway of the tool 10. During the drilling operation, the pistons 54, 56 and 70 are retained in the retracted position as will hereafter be described in detail and the tool 10 functions as a conventional stabilizer by reason of the fins 26.

After the bit has become dull, or when it is desired to take a fluid sample, the valve member 128 is allowed to pass downwardly through the drill stem, preferably by gravity, until it comes to rest on the seat 126, and the tool is positioned opposite the formation to be sampled. The restrictive orifice 157 through the secondary valve member 156 establishes a suflicient pressure differential between the high pressure port 130 and the low pressure port 134 to move the pistons 54 and 56 outwardly against the force of the springs 66 and 68 and shear the pins 188 and 190. When the resilient material 90 of the sealing pad 84 has been pressed tightly against the wall of the formation as illustrated in FIGURE 7, additional pressure is applied until the piston 70 is driven against the force of the spring 80 and the net hydraulic force acting on the sampling tube to drive the point 92 of the sampling tube 74 through the resilient material and into the wall of the formation. It will be noted that when the piston 70 and sampling tube 74 are in the retracted position illustrated in FIGURE 2, the ports 94 and 98 are disposed on opposite sides of the O-ring 116 so that the high pressure fluids in the well bore are blocked from entering the atmospheric pressure passageway 106. However, when the sampling tube 74 is moved outwardly through the valving sleeve 76 on the sample-taking stroke, the ports 94 and 98 are moved between the O-ring 116 and the O-ring 112 so that the high pressure fluids in the formation may pass through the annulus between the samplingtube 74 and the 'valve sleeve 76 to enter the port 98. The formation fluids then .pass through the port 106 and through the checkvalve 110 to fill the container 108 with the fluid sample.

' In operating the tool 10, the driller continually increases the volume of fluid pumped and therefore the pressure of the drilling :fluid as indicated at the surface. After the pressure drop across the valve member 128 has reached a sufliicently high level to insure that the pins 188 and 190 have been sheared, the pad pressed against the wall, and the sampling tube 74 has moved out and penetrated the wall of the borehole, the pin in the valve member 128 shears so that the secondary valve member 156 drops to the position illustrated in dotted outline in FIGURE 6. This results in an instantaneous decrease in the pressure of the drilling fluid at the surface which indicates to the driller that a sufficient pressure has been eestablished across the tool 10 to accomplish the sampling cycle. Fluid is continued at a high rate until the pressure in the receptacle has had time to equalize and thereby provide a measure of the formation pressure. Circulation of the drilling fluid is then terminated so as to equalize pressure in the ports 130 and 134. The springs 66, 68 and then return the sealing pad assembly 84 and sampling tube 74 to the retracted positions so that the tool can be raised from the boreholes. After the tool 10 is disconnected from the drill string at the surface, the receptacle 108 may be easily disconnected from the body 18 at the threaded coupling 120. The check valve prevents the loss of the fluid within the receptacle which is at the bottom hole pressure, and the receptacle can be transported to a lab for analysis without transferring the fluids.

It will normally be desirable to refurbish the tool 10 between each trip so as to insure proper operation. This can be relatively easily accomplished by disassembling the sampling mechanism and thoroughly cleaning the various cylinders and ports, then reassembling the tool using a new pad assembly 84 and receptacle if neecessary, and new shear pins 188 and 190.

During normal drilling operations, the pistons 54, 56 and 70 are retained in the retracted position. The pressure within the cylinders on either side of thee three pistons is substantially equalized by reason of fluid communication with substantially the same point in the primary fluid passageway through ports and 134. However, there is a net force acting on the pisto 54 equal to the area of the rod 58 multiplied by the difference in the pressure within the tool 10 and the pressure around the tool in the well bore, which is roughly equal to the pressure drop through the bit which can be rather high. A similar force is applied to the piston 56. These imbalances are offset by the force of the springs 66 and 68 and by the strength of the shear pins 188 and 190. An opposite hydraulic imbalance acts on the piston 70 because atmospheric pressure is acting over an area of the piston equal to the cross-sectional area of the tube 100 multiplied by the difference between the pressure outside the drill stern and atmospheric pressure in the container 108 and passageway 106. This pressure differential may be many thousands of pounds per square inch. This force is far greater than the force resulting from the pressure differential due to the pressure drop across the bit which acts on an area equal to the cross-sectional area of that portion of the sampling tube disposed around the tube 100. Therefore, the net hydraulic force acting on the piston 70 and sampling tube 74 acts strongly in a direction tendingto retain the sampling tube in the retracted position shown. The spring 80 assists in holding the piston 70 in the retracted position relative to the valve sleeve 76. It is important that the various piston areas, spring forces and shear forces be selected so that the sealing pad and the sampling tube will be retained in the retracted position during normal drilling operation. Then as the pressure differential is increased, the sealing pad should extend into contact with the wall of the well bore before the sampling'tube moves relative to the valve sleeve and sealing pad. If desired, the shear pins 188 and 190 may be discarded, or shear pins may be provided to lock the sampling tube relative to the valve sleeve to insure the proper opera-ting sequence. After the sample is taken, the high pressure fluid trapped in the port 106 will tend to force the sampling tube and piston outwardly as the tool is raised to zones of lower pressure. Therefore, it is important that the spring in the center piston be compressed before the springs holding the outer pistons and sealing pad are retracted so that the sampling tube will move relative to the valve sleeve to release this pressure through the ports 94 and 98. Or a suitable means for venting the port 106 may be provided.

From the above detailed description of a preferred embodiment of the invention, it will be appreciated that a fluid sampling tool has been described which can be used in a drill stem without interfering with the normal drilling operation. Further, the tool functions as a conventional stabilizer during the normal drilling operation. The operation of the tool 10 is accomplished by means of the power of the drilling fluid and the valve assembly 128 provides a means for indicating when the sampling operation has been accomplished. The novel sampling tool insures that the fluid sample is taken from the formation around the well bore, rather than merely sampling the fluids in the well bore by reason of both the sealing pad 84 which restricts the fluid standing in the borehole from the sampling zone, and by the penetration of the sampling tube into the formation. Further, a novel valving mechanism is provided whereby the sampling fluid enters the container only upon extension of the sampling tube into the formation. The receptacle can easily be removed from the tool for transport to the lab if desired without transfer to another container.

Although a preferred embodiment of the invention has been described in detail, it is to be understood that various changes, substitutions and alterations can be made in the specific construction of the various parts, and in the combination of the parts, without departing from the spirit and scope of the appended claims which are intended to constitute the sole limitation upon the scope of this invention.

What is claimed is:

1. In a fluid sampling tube, the combination of:

a sub for connection in a drill stem having a longitudinally extending primary fluid passageway therethrough for passing drilling fluid and an annular valve seat formed around the primary fluid passageway and facing up the drill stern,

three generally parallel fluid cylinders disposed transversely of the sub and spaced longitudinally along the sub, each cylinder having first and second ends,

first fluid passageway means formed in the sub for providing fluid communication between the first ends of the three cylinders and the primary fluid passageway on the high pressure side of the annular valve seat,

a first fluid piston reciprocally disposed in the center cylinder,

a fluid sampling tube connected to the first fluid piston and extending through the second end of the center cylinder,

second and third fluid pistons reciprocally disposed in the two outer cylinders, having piston rods extending through the second ends of the cylinders,

a sealing pad assembly having a resilient surface for engaging the wall of the borehole and isolating a sampling zone on the wall connected to the rods connected to the second and third fluid pistons,

a valve sleeve connected to the sealing pad assembly and reciprocally disposed in the second end of the center cylinder and slidably disposed around the sampling tube,

a valve member for seating on the annular valve seat to divert fluid pressure through the first fluid passageway to the first ends of the cylinders to move the pistons from retracted position to extended position where the sealing pad contacts the wall of the borehole, and to further move the first piston until the sampling tube is extended relative to the valve sleeve to contact the wall of the borehole,

a second and third fluid passageway extending from the opposite ends of the fluid sampling tube to longitudinally spaced points on the surface of the sampling tube,

an annular sealing means connected to the valve sleeve for sealing the annular space between the sampling tube and the valve sleeve, the sealing means being disposed between the longitudinally spaced points of emergence of the second and third fluid passageways when the sampling tube is retracted relative to the valve sleeve to seal the second fluid passageway from the third fluid passageway, and on one side of the spaced points when the sampling tube is extended to place the second and third passageways in fluid communication,

a tube extending from the first end of the center cylinder and slidably received in the first piston, the interior of the tube being in fluid communication with one of the fluid passageways extending through the sampling tube, the tube being sealed with the first piston, and

a fluid receptacle in fluid communication with the interior of the tube for receiving a fluid sample when the sampling tube is extended.

2. The combination defined in ,claim 1 wherein:

the fluid receptacle is threadedly connected in the sub and includes a check valve in the inlet passageway thereof to permit high pressure fluid to enter the receptacle and to prevent the escape of the fluid from the receptacle.

3. The combination defined in claim 1 further characterized by:

a plurality of elongated stabilizer fins extending longitudinally along the sub for maintaining the sub substantially centered in the borehole while a fluid sample is being taken.

4. The combination defined in claim 1 further characterized by:

compression spring means disposed in each of the outer cylinders between the second and third pistons and the second ends of the cylinders, and in the center cylinder between the first piston and the valve sleeve.

5. In a sidewall fluid sampling tool, the combination of:

a sub for connection in a drill stem having a primary fluid passageway extending longitudinally through the sub for passing drilling fluid through the sub,

a fluid cylinder formed in the sub having first and second ends,

a fluid piston reciprocally disposed in the cylinder,

a first fluid passageway in the sub providing fluid communication between the primary fluid passageway and the first end of the cylinder, 7

a fluid sampling tube connected to the piston and extending through the second end of the cylinder for penetrating the wall of a borehole and having a fluid passageway therethrough for receiving a fluid sample from the wall,

first valving means for selectively applying fluid pressure from the primary fluid passageway to the first fluid passageway to drive the piston and sampling tube on a sampling stroke,

a fluid receptacle at a pressure lower than the formation pressure, and

valving means for placing the receptacle in fluid communication with the fluid passageway through the sampling tube when the sampling tube has extended, whereby well fluids will enter the receptacle, and for retaining fluid in the receptacle as it is withdrawn from the well bore.

6. In a sidewall fluid sampler, the combination of:

a housing for insertion in a borehole,

three generally parallel fluid cylinders formed in the housing and generally aligned to provide a center cylinder and two outer cylinders, each of the cylinders having first and second ends,

a fluid piston reciprocally disposed in each cylinder,

a piston rod connected to each of the pistons in the outer cylinders and extending through the second ends of the respective. cylinders,

a sealing pad assembly connected to the ends of the rods extending from the outer cylinders and extending adjacent the second end of the center cylinder,

a valve sleeve connected to the sealing pad assembly and slidably extending into the second end of the center cylinder,

a fluid sampling tube connected to the piston in the center cylinder and slidably disposed in and extending through the valve sleeve,

fluid passageway means extending from the end of the sampling tube through the tube,

a sample receiving receptacle for a gas at a relatively low pressure,

means for applying power fluid to the first ends of the cylinders to move the pistons outwardly until the sealing pad assembly contacts the Wall of the borehole and then for moving the sampling tube through the valving sleeve and the sealing pad assembly into the wall of the borehole, and

port and land means on the valve sleeve and sampling tube for placing the receptacle in fluid communication with the fluid passageway through the sampling tube whereby any high pressure fluid in the wall of the well bore will enter the receptacle. 7. In a sidewall fluid sampling tool, the combination of:

a housing for insertion in a well bore,

a sampling tube disposed in the housing for longitudinal movement between retracted and extended positions,

a valve sleeve around the sampling tube,

means for moving the sampling tube through the valve sleeve from retracted to extended positions,

a first fluid passageway extending through the sampling tube from the extending end to a midpoint on the surface of the sampling tube,

a second fluid passageway extending from a point at the surface of the sampling tube spaced from the first fluid passageway for communicating with a receptacle for receiving a fluid sample, and

annular sealing means connected to the valve sleeve and disposed between the first and second fluid passageways when the sampling tube is in the retracted position to seal the second fluid passageway from the first, and not between the passageways when the sampling tube is extended whereby the passageways will be in fluid communication and high pressure fluid can pass to the receptacle.

References Cited CHARLES E. OCONNELL, Primary Examiner.

DAVID H. BROWN, Examiner. 

7. IN A SIDEWALL FLUID SAMPLING TOOL, THE COMBINATION OF: A HOUSING FOR INSERTION IN A WELL BORE, A SAMPLING TUBE DISPOSED IN THE HOUSING FOR LONGITUDINAL MOVEMENT BETWEEN RETRACTED AND EXTENDING POSITIONS, A VALVE SLEEVE AROUND THE SAMPLING TUBE, MEANS FOR MOVING THE SAMPLING TUBE THROUGH THE VALVE SLEEVE FROM RETRACTED TO EXTENDED POSITIONS, A FIRST FLUID PASSAGEWAY EXTENDING THROUGH THE SAMPLING TUBE FROM THE EXTENDING END TO A MIDPOINT ON THE SURFACE OF THE SAMPLING TUBE, A SECOND FLUID PASSAGEWAY EXTENDING FROM A POINT AT THE SURFACE OF THE SAMPLING TUBE SPACED FROM THE FIRST FLUID PASSAGEWAY FOR COMMUNICATING WITH A RECEPTACLE FOR RECEIVING A FLUID SAMPLE, AND ANNULAR SEALING MEANS CONNECTED TO THE VALVE SLEEVE AND DISPOSED BETWEEN THE FIRST AND SECOND FLUID PASSAGEWAYS WHEN THE SAMPLING TUBE IS IN THE RETRACTED POSITION TO SEAL THE SECOND FLUID PASSAGEWAYS WHEN THE FIRST, AND NOT BETWEEN WHEREBY THE PASSAGEWAYS SAMPLING TUBE IS EXTENDED WHEREBY THE PASSAGEWAYS WILL BE IN FLUID COMMUNICATION AND HIGH PRESSURE FLUID CAN PASS TO THE RECEPTACLE. 